As semiconductor wafer fabrication evolves, device geometries become smaller, which provides greater densities that drive down costs, decrease device sizes, increase functionalities, enable increasing levels of integration, or any combination thereof. Increases in densities tend to drive down operating voltages, and semiconductor fabrication processes have evolved toward lower operating voltage processes; however, certain applications require relatively high operating voltages. For example, in a wireless communications device, such as a cell phone, high density computing integrated circuits (ICs) are needed to provide desired functions, such as graphic displays, digital camera functionality, audio player functionality, or the like. However, in the radio frequency (RF) section, antenna switching between a transmitter and a receiver may use a microelectromechanical system (MEMS) switch, which may require an activation voltage greater than 60 volts. Certain graphic displays may require a voltage greater than 20 volts.
To reduce size, cost, and power consumption, it is desirable to integrate low-voltage circuitry, such as computing circuitry, clocks, dividers, memory, decoders, logic, and any other digital circuitry, with high-voltage circuitry, such as a MEMS switch, associated MEMS interface circuitry, and a low-to-high voltage converter, such as a charge pump, on a single semiconductor die, which is provided from a wafer that is fabricated using low-voltage foundry technology. Thus, there is a need to develop high-voltage devices that can be fabricated using low-voltage foundry technology. Specifically, there is a need to develop high-voltage interface and power supply circuitry using the high-voltage devices, and to integrate low-voltage circuitry and the high-voltage interface circuitry on a single semiconductor wafer that is fabricated using the low-voltage foundry technology. Additionally, there is a need to further integrate a high-voltage device, such as a MEMS switch, on the single semiconductor wafer.